Astropolis, the largest city in the solar system, is located in the Asteroid Belt. It can best be described as an array of asteroid cities (City Asteroids) functioning as joints in a carbonfiber web. The carbonfiber web, using gravity, keeps the system in balance. Each carbonfiber acts as a transportation system, using the same concept as the Anderson Space Elevator.

In 2037 nanobots began the Astropolis construction, by turning asteroids into City Asteroids. Not much is left of the asteroids themselves, only their outer crust for protection. Inside and on the surface people live and work. You can find everything there, shopping centres, schools, greenhouses and of course a fusion reactor. Most of the complexes created by the nanobots still have to be occupied. This is because mass emigration to the Asteroid Belt has only recently been approved by the ISA.